1. Field of the Invention
The disclosure relates to a power distribution technique, and in particular, to a technique in which power is controlled in a system where a storage battery connected to a renewable energy power generator and a commercial power supply are used in combination.
2. Description of the Related Art
A technique has been developed, in which a storage battery and a commercial power supply are connected to a load in parallel thereto, so that the storage battery is used as a backup for the power consumed in the load in preparation for when the commercial power supply is in a power failure state, and in a normal time, the power in the storage battery is discharged for the peak shaving of the power consumed in the load. In such a technique, the AC power from the commercial power supply is converted into DC power to be stored in the storage battery in a time zone when the power consumed by the load is little, for example, at night, etc., and the power in the storage battery is converted into AC power to be supplied to the load in a time zone when the power consumed by the load is much, for example, at daytime, etc.
In order to control the aforementioned power conversion etc., a dedicated power conversion device may be used. In relation to such a technique, a technique is proposed, in which the operation mode of the power conversion device is switched when an abnormal thing is detected in the commercial power system (see Japanese Unexamined Patent Application Publication No. 2011-10412).